Oil burner



March 17, 1936. Cl A SCHELLENS 2,@34-,210

OIL BURNER Filed March 16, 1953- 2 Sheets-Sheet 1 INVENTOR March 17,1936. c, A. scHELLENs OIL BURNER Filed Ma'rch 16, 1933 2 Sheets-Sheet-2INVENTOR Patented Mar. 17, 1936 UNITED STATES nino Aralar ri ApplicationMarch 16,

16 Claims.

My invention relates to liquid fuel burners in which the fuel, usuallyoil, is atomized before burning.

The burner is of the air driven rotating atomizing cup type in which oilis atomized by being thrown from the open end of the atomizing cup. Inoil burning plants of the average size, employing this type of burner asusually constructed, the blowers which supply air to the burners, andwhich do not form a part of this invention, operate under conditions ofexcessively high delivery pressure and excessively low delivery volumes.An increase in the blower delivery pressure causes a more thanp-roportional increase in power consumption as well as in cost of theblower, whereas an increase in volume causes a less than proportional,and frequently insignificant, increase in power consumption and cost. Itis one of the objects of my invention to secure the high rotative speedof the atomizing cup necessary for proper atomization by the employmentof a larger air volume and a lower air pressure, whereby the blowerwhich supplies air to the burner can be built at a lower cost, andrequires less power for its operation.

In burners of this type as usually constructed, difculty is encounteredin obtaining a uniform speed of the atomizing cup. The resistance torotation of the rotating elements is subject to wide variation due tovarying viscosity of the bearing lubricating oil, foreign matter in thebearings, and varying rates of atomization. It is a further object of myinvention to provide means whereby a substantially uniform speed ofrotation is obtained irrespective of the aforesaid variable r-esistance.

Another object of my invention is to generally improve the constructionand operation o-f oil burners.

In the accompanying drawings which form a part of this specification:

Fig. 1 is a vertical central longitudinal section of the burner,

Fig. 2 is a developed partial section of the air turbine wheel andturbine nozzle made by a circular cylinder coaxial with the shaft axisand passing through the line A-A, Fig. l,

Fig. 3 is an elevation from the rear end, of one of the speed governorweights, and

Fig. 4 is a vertical central longitudinal section of the burnerconstructed in a modified form.

My invention includes an approximately cone shaped outer casing I havingthe air inlet connection 2, which may be used for supporting the 1933,Serial No. 651,027

(Cl. 15S- 77) burner. which we may designate for convenience as thefront end, carries an atomizer air nozzle 3, through which air passesinto a furnace or other combustion space, mixing with and directing theatomized fuel.

Extending through and supported at the large end of the outer casing I,I provide an inner casing 4, which sup-ports the rotating members of theburner. The front end of the said inner casing is substantially conical,and is separated from the rear end by the partition wall 5, forming thefront compartment 5 and the rear compartment 'I.

A ball bearing retainer 5 is bolted or otherwise suitably joined to thepartition wall 5, and serves to support the ball bearing 9. Ball bearingI9 is supported by the front end of the inner casing The small end ofthe outer casingA Il, and is restrained from forward motion by the innercasing front end cover II. The shaft I2 which supports the atomizing cupI3 and the air turbine wheel I4 is journalled by the'ball bearings 9 andI0.

The atomizing cup I3 is preferably secured to the shaft I2 by means ofthe screw thread I5 and taper t IB whereby it may be convenientlywithdrawn for inspection. The atomizing cup I3 is provided with a hub Ilwhich is integral with the shell and divides the cup into front and rearcompartments I 8 and I9 respectively. The said hub is provided with aplurality of passages 2i! whereby communication is established betweenthe front compartment I8 and the rear compartment I9. The rear end ofthe cupi is provided with a flangey 2i for the purpose of preventing theoil to be atomized from spilling rearwardly.

As here shown oil is led to the atomizing cup I3 through the pipe 22,which is provided at its rear end with the pipe connection 59.

At itsfront end the pipe 22 is joined by means of a'v pipe thread to thecover II, and passages 23 and z 24 are provided in the said cover forthe purpose of conducting oil to the interior of the atomiz ing cup I 3.

The air turbine wheel I4 is mounted on the shaft I2 at the rear of andadjacent to the ball bearing 9, and is prevented from turning on theV'said shaft by the key 2l. The said turbine wheel is provided with aplurality of spaced turbine buckets or vanes 29 which are shown insection in shown in section in Fig. 2.V The said turbine nozzle directsthe air from the annular space between the outer casing I and the innercasing 4 against the buckets 28 an-d causes the turbine wheel I4 torotate rapidly.

Ball bearings 9 and i3 are'lubricated by means ofthe oil ring 3! whichdips into lubricating oil contained in the lower part of the forwardcompartment 6. The shaft is preferably tapered, the large end beingadjacent to the forward ball bearing IEl whereby a film of lubricatingoil impelled by centrifugal force finds its way into the forward ballbearing.

The rear compartment 'I surrounds the turbine wheel I4, an-d is providedwith a cone shaped cover 32 having a central orifice 33, whereby airfrom the turbine is exhausted to the outside. The cover 32 is providedwith bosses 34 to which is attached baiiie plate 35, which plate has thepurpose of deecting and diffusing the air issuing from the said orifice.

For the purpose of controlling the speed of the rotating members of theburner I provide speed governing means including governor weights 36,

`which are -pivod on the cone shaped ends of the hardened steel pins 37,which pins are screwed or otherwise suitably fastened to the turbineWheel I4. As shown in Fig. 3 each governor weight consists of a hardenedsteel base 38 to which is secured the metal cylinder 39.

The said base is provided with a semicircular recess 40 in which the endof the pin 3i pivots. The slot 4| straddles the shaft I2 and provides aguide which prevents sidewise motion of the said governor weights.

Under the inuence of centrifugal force the slotted ends of the bases 38bear against the hardened steel bushing 42, which is guided forlongitudinal motionV by the shaft I2, and which supports the governorsleeve 43, to which it is suitably attached. The rearward motion of thegovernor sleeve 43 due to the action of the cen- Y trifugal force of theweights 3B is resisted, and

'governor spring 44.

the said centrifugal force is balanced, by the The said spring bearsagainst the nut 45 which is screwed to the end of the shaft. The saidnut serves as a guide for the rear end of the governor sleeve 43, and,cooperating with the spring 44, and governor weights 36, secures theturbine wheel longitudinally against the ball bearing 9.

'Ihe governor sleeve 43 is provided with a flange 45 Ywhich operates toopen or close the orifice 33 asthe governor weight cylinders 3S move inor out respectively. By this means the air leaving compartment I isthrottled, and the air pressure Within the said compartment is raised orlowered by the action of the speed governing means aforesaid, wherebythe force of the ai;n stream directed against the buckets 28 is variedas required for the maintenance of a substantiallyv constant speed ofthe aforesaid rotating members.

While I'secure all of the objects `of my invention bythe constructionwhich I have described,

fand which illustrates the preferred form of my Yinvention, I may omitthe automatic speed governing means as described and still secure someofthe objects.

IY may also arrange my invention with theV the turbine buckets 28a.Cover 32a is provided with bosses 34a to which is attached the plate35a, which serves, as before, to deflect the air stream issuing from theaforesaid orifice. Plate 35a carries a threaded boss 5I through whichthe threadedstem 48 passes. The stem 48 carries the orifice plate 4l andthe handwheel 49. By the manipulation of the said handwheel the saidorice plate is moved in a longitudinal direction and throttles the airissuing from the said orifice, thereby regulating the speed of the saidatomizing cup as required.

While I have described the throttling means as arranged to throttle theair stream after passing through the turbine buckets, it is apparentthat similar results would be obtained if the air which passes throughthe turbine buckets were throttled before passing therethrough, and Iwish to have this feature of my invention construed broadly.

How the aforesaid objects and advantages are secured will now appear.Air at a substantially constant pressure, supplied by a blower or othermeans not forming a part of this invention, enters the burner at the airconnection 2. Part of the said air flows through the turbine nozzle 30and impinges on the buckets 28 of the air turbine wheel I4, causing itto rotate rapidly, the said rotation being transmitted to the atomizingcup I3. Oil is fed by means not forming a part of this invention to thepipe connection 50, through pipe 22, and cover I I, and subsequentlyflo-ws into the atomizing cup I3, from the open mouth of which it isejected by centrifugal force in a nely divided state.

In burners of this type as usually constructed the air first passesthrough the air turbine and subsequently through the air nozzle. The airturbine and the atomizer nozzle may be regarded as operating in serieswith reference to the air fl'ow. In a burner constructed in accordancewith my invention, on the other hand, the air turbine and the atomizernozzle are arranged in parallel. It is apparent that in the abovedescribed usual arrangement the 'pressure of the air which must besupplied to the-burner is the sum of the pressure drop through theturbine, including its nozzle, and the pressure drop throughy theatomizing nozzle.

In a burner constructed in accordance with invention, on the other hand,the pressure of the air which must be supplied to the burner `must beequal to the larger of the two aforementioned pressure drops. In theoperation of Y oil burners under the usual conditions it is found thatthe pressure drop through the atomizer nozzle is greatly in excess ofthe pressure drop taking place in the turbine propelling elements,namely the turbine nozzle and buckets, provided the said turbineelements are constructed efnciently. The volume of air supplied to theburner, on the other hand, is greater tha-n in the case of a burner ofthe usual construction. My'

' form a part of my invention is to utilize the eX- cess pressure dropavailable for driving the turbine as a reserve to provide for theresistance to rotation, caused by the atomization of large oil iiows,and by increased bearing friction due to foreign matter in the bearingsand excessive viscosity of the bearing lubricating oil. Thus, undernormal conditions the pressure drop available for driving the turbine isreduced, either by the manually operated air throttling means as shownin Fig. 4, or, automatically, by the centrifugal speed governing meansas described. Under conditions of unusual resistance to rotation thethrottling action is reduced, and more of the available pressure drop isapplied to the driving of the turbine. In this way I obtain a constantspeed of the atomizing cup.

If, as an example, we have reference to a burner of a specific rating,in which a pressure drop of 8 inches water column is required throughthe atomizer nozzle, and a pressure drop of 4 inches water column isrequired to drive the turbine at the proper speed of rotation, it isapparent that in a burner of the usual construction air at a pressure ofl2 inches water column must be supplied to the burner. Furthermore,under 'conditions of unusual resistance to rotation, the

speed of the atomizing cup decreases.

On the other hand, in a burner constructed in accordance with myinvention, and having reference to the abovementioned example, air at apressure of 8 inches water column is satisfactory for the operation ofthe burner. Furthermore a pressure drop of 8 inches water column isavailable for driving the turbine, which provides for a reserve of 4inches water column, whereby the necessary rotative speed of theatomizing cup is maintained under conditions of the foresaid unusualresistances to rotation.

The structure of my invention may be otherwise modified withoutdeparting from the spirit thereof.

I claim:

1. In a liquid fuel burner the combination of a rotatably mounted fuelatomizing member, means for conducting fuel to the interior thereof, airactuated means arranged for driving said member, means for conductingair to said atomizing member and said air actuated means, whereby aportion of said air is conducted exclusively so as to mix with anddirect fuel atomized by said fuel atomizing member, and another portionof said air is conducted exclusively so as to actuate said air actuatedmeans, and means responsive to the speed of rotation of said atomizingmember for regulating the speed thereof.

2. In a liquid fuel burner the combination of a rotatably mounted fuelatomizing member, means for conducting fuel to the interior thereof, airactuated means arranged for driving said member, including turbinebuckets, a turbine nozzle cooperating with said buckets, means forconducting air to' said atomizing member and said turbine nozzle wherebya portion of said air is conducted exclusively so as to mix with anddirect fuel atomized by said fuel atomizing member, and another portionof said air is conducted exclusively to said turbine nozzle and actuatessaid air actuated means, throttling means arranged t0 control the flowof air through said turbine nozzle, by throttling said air subsequent toits actuating. said air actuated means and a centrifugal speed governorcooperating with said throttling means whereby the speed of rotation ofsaid atomizing member is maintained substantially constant.

3. In a liquid fuel burner the combination of a rotatably mounted fuelatomizing member, means for conducting fuelV to the interior thereof',air actuated means arranged for driving said member including turbinebuckets, a turbine nozzle cooperating with said buckets, means forconducting air to said atomizing member and said tubine nozzle whereby aportion of said air is conducted exclusively so as to mix with anddirect fuel atomized by said fuel atomizing member, and another portionof said air is conducted exclusively to said turbine nozzle and actuatessaid air actuated means, and means adapted to manual operation forthrottling the air which passes through said turbine nozzle subsequentto its actuating said air actuated means, whereby the speed of rotationof said atomizing member is manually controlled.

4. In a liquid fuel burner the combination of a rotatably mounted fuelatomizing member, air actuated means driving said member, a casingenclosing said air actuated means and provided with an orifice wherebyair is discharged therefrom after actuating said air -actuated means,and throttling means cooperating with said orifice whereby airdischarged therethrough isthrottled and the speed of said member iscontrolled.

5. In a liquid fuel burner the combination of a rotatably mounted fuelatomizing member, an air actuated turbine driving said member, a casingenclosing said turbine provided with an orice whereby air dischargedfrom said turbine escapes from said casing, and throttling meanscooperating with said orifice whereby said air is throttled, saidthrottling means including a centrifugal speed governor responsive tothe speed of said turbine.

6. In a liquid fuel burner the combination of a casing, a shaft mountedfor rotation, a fuelv atomizing member mounted on one end of said shaft,an air actuated turbine mounted for driving said shaft on the other endthereof, a plurality of bearings mounting said shaft in said casing, andmeans exterior to said shaft for conducting fuel to said fuel atomizingmember, said bearings being located between said atomizing member andsaid turbine.

'7. In a liquid fuel burner of the kind described the combination of afuel atomizing cup, means for conducting fuel to the interior thereof, acompressed air actuated turbine driving said cup, and means responsiveto the speed of rotation of said cup whereby said speed is regulated.

8. In a liquid fuel burner the combination of a member rotatable toatomize fuel exclusively by centrifugal projection therefrom, compressedair actuated means rotating said member, and means regulating the speedof said member responsive to the speed of rotation thereof.

9. In a liquid fuel burner the combination of a compressed air actuatedmember rotatable to atomize fuel exclusively by centrifugal projectiontherefrom, and means responsive to speed changes in the rotation of saidmember for maintaining said speed substantially constant including acentrifugal governor.

10. In a liquid fuel burner the combination of an atomizing membermounted for rotation, an air actuated turbine mounted for driving saidmember, a casing surrounding said turbine and provided with an exhaustorifice, turbine actuating air supply means discharging into saidcasing, and a centrifugal speed governor responsive to the speed of saidturbine, and cooperating with said orifice to throttle the actuating airexhausted from said turbine, said. atomizing member, said turbine, saidgovernor, and' said'oriflce being coaxially disposed. Y

11. In a liquid :fuel burner the combination of aturbine, a fuelatomizing cup rotated by said turbine, a casing enclosing said turbineprovided with a turbine exhaust orifice, and aV centrifugal speedgovernor cooperating With said orifice to maintain a substantiallyconstant speed of rotation of said cup. Y l

Y12. In a liquid fuel burner the combination of a rotatably mounted fuelatomizing cup, an air actuated turbine rotating said cup, a turbinedriving nozzle, a casing enclosing said turbine provided with an exhaustorifice, an air nozzle discharging adjacent to, and directing theatomized fuel as it leaves said cup, branched air conducting meansconducting air under pressure from a common source to said turbineVdriving nozzle and said fuel directing nozzle, and a centrifugal speedgovernorV cooperating With-said orifice to throttle the air passingthrough said turbine to maintain the speed of said atomizing cupsubstantially constant.

13. In a liquid fuel burner the combination of a fuel atomizing membermounted for rotation, means for conducting fuel thereto, an airactuated'turbine member including buckets, mounted in driving relationto said member, an air nozzle discharging adjacent to, and directing theatomized fuel as it leavessaid atomizing member, an enclosuresurrounding said turbine member provided with an orifice communicatingwith the atmosphere, branched air conducting means whereof one branchconducts exclusively driving air to flow through said turbine member,into said enclosure, and through said orifice in succession, and anotherbranch conducts exclusively fuel directing air to said Vair nozzle, andair throttling means cooperating with said orifice to throttle the airissuing therefrom.

14. In aiiquia fuei burner the combination of Y flow through said airactuated means in driving relation thereto, into said casing, andthrough said orifice in succession, and another branch conductsexclusively fuel directing air to the fuel atomized'` by said atomizingmember, and throttling means including a centrifugal speed governorresponsive to the speed of said air actuated means, cooperating withsaid orifice to throttle said driving air. Y

15. In a liquid fuel burner the combination of a fuel atomizing memberrotatable to atomize fuel exclusively by centrifugal projectiontherefrom, an air nozzle discharging adjacent to, and directing theatomized fuel as it leaves said member, an air turbine wheel drivingsaid member, a turbine nozzle conducting driving air to said turbine,and means for conducting air to said air nozzle and said turbine nozzleat one and the same pressure.

16.V In a liquid fuel burner the combination of a fuel atomizing memberrotatable to atomize .Y fuel exclusively by centrifugal projectiontherefrom, an air nozzle discharging adjacent to, and directing theatomized fuel as it leaves said member, air actuated means driving saidmember, and branched air conducting means for conducting air underpressure from a single source to said nozzle for directing said fuel,and to said air actuated means for the actuation thereof.

CHRISTOPHER A. SCHELLENS.

